scholarly journals Strigolactones Control Root System Architecture and Tip Anatomy in Solanum lycopersicum L. Plants under P Starvation

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 612 ◽  
Author(s):  
Veronica Santoro ◽  
Michela Schiavon ◽  
Francesco Gresta ◽  
Andrea Ertani ◽  
Francesca Cardinale ◽  
...  
Keyword(s):  
Solanum Lycopersicum ◽  
Lateral Root ◽  
Primary Root ◽  
Root Traits ◽  
Root System Architecture ◽  
Root Tip ◽  
Root Number ◽  
Wild Type ◽  
Solanum Lycopersicum L ◽  
P Supply

The hormones strigolactones accumulate in plant roots under phosphorus (P) shortage, inducing variations in plant phenotype. In this study, we aimed at understanding whether strigolactones control morphological and anatomical changes in tomato (Solanum lycopersicum L.) roots under varying P supply. Root traits were evaluated in wild-type seedlings grown in high vs. low P, with or without exogenous strigolactones, and in wild-type and strigolactone-depleted plants grown first under high vs. no P, and then under high vs. no P after acclimation on low P. Exogenous strigolactones stimulated primary root and lateral root number under low P. Root growth was reduced in strigolactone-depleted plants maintained under continuous P deprivation. Total root and root hair length, lateral root number and root tip anatomy were impaired by low strigolactone biosynthesis in plants grown under low P or transferred from low to no P. Under adequate P conditions, root traits of strigolactone-depleted and wild-type plants were similar. Concluding, our results indicate that strigolactones (i) control macro- and microscopic changes of root in tomato depending on P supply; and (ii) do not affect root traits significantly when plants are supplemented with adequate P, but are needed for acclimation to no P and typical responses to low P.

scholarly journals AT-HOOK MOTIF NUCLEAR LOCALISED PROTEIN 18 as a Novel Modulator of Root System Architecture

2020 ◽  
Author(s):  
Marek Šírl ◽  
Tereza Šnajdrová ◽  
Dolores Gutiérrez-Alanís ◽  
Joseph G. Dubrovsky ◽  
Jean Phillipe Vielle-Calzada ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Apical Meristem ◽  
Lateral Roots ◽  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Initiation ◽  
Lateral Root Initiation

The AT-HOOK MOTIF NUCLEAR LOCALIZED PROTEIN (AHL) gene family encodes embryophyte-specific nuclear proteins with DNA binding activity. They modulate gene expression and affect various developmental processes in plants. We identify AHL18 (At3G60870) as a developmental modulator of root system architecture and growth. AHL18 regulates the length of the proliferation domain and number of dividing cells in the root apical meristem and thereby, cell production. Both primary root growth and lateral root development respond according to AHL18 transcription level. The ahl18 knock-out plants show reduced root systems due to a shorter primary root and a lower number of lateral roots. This change results from a higher number of arrested and non-developing lateral root primordia (LRP) rather than from decreased initiation. Overexpression of AHL18 results in a more extensive root system, longer primary roots, and increased density of lateral root initiation events. Formation of lateral roots is affected during the initiation of LRP and later development. AHL18 regulate root apical meristem activity, lateral root initiation and emergence, which is in accord with localization of its expression.

scholarly journals Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

2017 ◽  
Vol 114 (17) ◽  
pp. E3563-E3572 ◽  
Author(s):  
Javier Mora-Macías ◽  
Jonathan Odilón Ojeda-Rivera ◽  
Dolores Gutiérrez-Alanís ◽  
Lenin Yong-Villalobos ◽  
Araceli Oropeza-Aburto ◽  
...  
Keyword(s):  
Primary Root ◽  
Root System Architecture ◽  
Root Apical Meristem ◽  
Root Tip ◽  
Al Tolerance ◽  
Short Root ◽  
Meristematic Cells ◽  
Isolation And Characterization ◽  
Root Response ◽  
Primary Root Growth

Low phosphate (Pi) availability constrains plant development and seed production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance the soil exploration ability of the plant and lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent mechanism reprograms primary root growth in response to low Pi availability. This program is activated upon contact of the root tip with low-Pi media and induces premature cell differentiation and the arrest of mitotic activity in the root apical meristem, resulting in a short-root phenotype. However, the mechanisms that regulate the primary root response to Pi-limiting conditions remain largely unknown. Here we report on the isolation and characterization of two low-Pi insensitive mutants (lpi5 and lpi6), which have a long-root phenotype when grown in low-Pi media. Cellular, genomic, and transcriptomic analysis of low-Pi insensitive mutants revealed that the genes previously shown to underlie Arabidopsis Al tolerance via root malate exudation, known as SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1), represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana. Our results also show that exogenous malate can rescue the long-root phenotype of lpi5 and lpi6. Malate exudation is required for the accumulation of Fe in the apoplast of meristematic cells, triggering the differentiation of meristematic cells in response to Pi deprivation.

Identification of chromosomal deficiency by flow cytometry and cytogenetics in mutant tomato (Solanum lycopersicum, Solanaceae) plants

2009 ◽  
Vol 57 (5) ◽  
pp. 444 ◽  
Author(s):  
Isane Vera Karsburg ◽  
Carlos Roberto Carvalho ◽  
Wellington Ronildo Clarindo
Keyword(s):  
Flow Cytometry ◽  
Solanum Lycopersicum ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Chromosome 1 ◽  
Wild Type ◽  
Extrinsic Factors ◽  
Solanum Lycopersicum L ◽  
Morphogenic Process

Structural chromosomal aberrations can occur spontaneously in plant karyotypes as a result of both intrinsic and extrinsic factors. These aberrations may affect sporophyte fitness because fundamental genes involved with distinct morphogenic process may be lost. Inadequate development of flowers and anomalous fruits without seeds has been observed in plants of Solanum lycopersicum L. (Solanaceae) ‘BHG 160’ of the tomato germplasm bank (Universidade Federal de Viçosa, Brazil). The nuclear DNA content, quantified by flow cytometry, showed that mutant ‘BHG 160’ possesses 0.09 pg (4.59%) less nuclear DNA content than does the wild-type ‘BGH 160’. Improved cytogenetical preparations evidenced that this difference was due to a spontaneous terminal deficiency in the short arm of the mutant ‘BGH 160’ Chromosome 1. These results suggest that the genes encoded in the short arm of Chromosome 1 may be involved in the development of flowers and fruits in the tomato.

scholarly journals CLE-CLAVATA1 Signaling Pathway Modulates Lateral Root Development under Sulfur Deficiency

Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 103 ◽  
Author(s):  
Wei Dong ◽  
Yinghua Wang ◽  
Hideki Takahashi
Keyword(s):  
Root Development ◽  
Lateral Root ◽  
Molecular Mechanisms ◽  
Plant Root ◽  
Root System Architecture ◽  
Wild Type ◽  
Lateral Root Development ◽  
S Deficiency ◽  
Cle Peptide ◽  
Plant Root System

Plant root system architecture changes drastically in response to availability of macronutrients in the soil environment. Despite the importance of root sulfur (S) uptake in plant growth and reproduction, molecular mechanisms underlying root development in response to S availability have not been fully characterized. We report here on the signaling module composed of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) peptide and CLAVATA1 (CLV1) leucine-rich repeat receptor kinase, which regulate lateral root (LR) development in Arabidopsis thaliana upon changes in S availability. The wild-type seedlings exposed to prolonged S deficiency showed a phenotype with low LR density, which was restored upon sulfate supply. In contrast, the clv1 mutant showed a higher daily increase rate of LR density relative to the wild-type under prolonged S deficiency, which was diminished to the wild-type level upon sulfate supply, suggesting that CLV1 directs a signal to inhibit LR development under S-deficient conditions. CLE2 and CLE3 transcript levels decreased under S deficiency and through CLV1-mediated feedback regulations, suggesting the levels of CLE peptide signals are adjusted during the course of LR development. This study demonstrates a fine-tuned mechanism for LR development coordinately regulated by CLE-CLV1 signaling and in response to changes in S availability.

scholarly journals Nitrate Induction of Primary Root Growth Requires Cytokinin Signaling in Arabidopsis thaliana

2019 ◽  
Vol 61 (2) ◽  
pp. 342-352 ◽  
Author(s):  
Pamela A Naulin ◽  
Grace I Armijo ◽  
Andrea S Vega ◽  
Karem P Tamayo ◽  
Diana E Gras ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Root Growth ◽  
Primary Root ◽  
Growth Arrest ◽  
Root Tip ◽  
Wild Type ◽  
Cytokinin Signaling ◽  
Control Growth ◽  
Primary Root Growth

Abstract Nitrate can act as a potent signal to control growth and development in plants. In this study, we show that nitrate is able to stimulate primary root growth via increased meristem activity and cytokinin signaling. Cytokinin perception and biosynthesis mutants displayed shorter roots as compared with wild-type plants when grown with nitrate as the only nitrogen source. Histological analysis of the root tip revealed decreased cell division and elongation in the cytokinin receptor double mutant ahk2/ahk4 as compared with wild-type plants under a sufficient nitrate regime. Interestingly, a nitrate-dependent root growth arrest was observed between days 5 and 6 after sowing. Wild-type plants were able to recover from this growth arrest, while cytokinin signaling or biosynthesis mutants were not. Transcriptome analysis revealed significant changes in gene expression after, but not before, this transition in contrasting genotypes and nitrate regimes. We identified genes involved in both cell division and elongation as potentially important for primary root growth in response to nitrate. Our results provide evidence linking nitrate and cytokinin signaling for the control of primary root growth in Arabidopsis thaliana.

scholarly journals Early development and gravitropic response of lateral roots in Arabidopsis thaliana

2012 ◽  
Vol 367 (1595) ◽  
pp. 1509-1516 ◽  
Author(s):  
S. Guyomarc'h ◽  
S. Léran ◽  
M. Auzon-Cape ◽  
F. Perrine-Walker ◽  
M. Lucas ◽  
...  
Keyword(s):  
Lateral Root ◽  
Developmental Plasticity ◽  
Lateral Roots ◽  
Expression Patterns ◽  
Primary Root ◽  
Root System Architecture ◽  
Specific Response ◽  
Root Induction ◽  
Root Gravitropism ◽  
Auxin Transporter

Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.

scholarly journals Shoot-derived miR2111 controls legume root and nodule development

2020 ◽  
Author(s):  
Mengbai Zhang ◽  
Huanan Su ◽  
Peter M. Gresshoff ◽  
Brett J. Ferguson
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Ectopic Expression ◽  
Root System Architecture ◽  
Negative Regulator ◽  
Nodule Development ◽  
Wild Type ◽  
Root Branching ◽  
Autoregulation Of Nodulation ◽  
Cle Peptide

AbstractLegumes control their nodule numbers through the Autoregulation Of Nodulation (AON). Rhizobia infection stimulates the production of root-derived CLE peptide hormones that are translocated to the shoot where they regulate a new signal. We used soybean to demonstrate that this shoot-derived signal is miR2111, which is transported via phloem to the root where it targets transcripts of Too Much Love (TML), a negative regulator of nodulation. Shoot perception of rhizobia-induced CLE peptides suppresses miR2111 expression, resulting in TML accumulation in roots and subsequent inhibition of nodule organogenesis. Feeding synthetic mature miR2111 via the petiole increased nodule numbers per plant. Likewise, elevating miR2111 availability by over-expression promoted nodulation, while target mimicry of TML induced the opposite effect on nodule development in wild-type plants and alleviated the supernodulating and stunted root growth phenotypes of AON-defective mutants. Additionally, in non-nodulating wild-type plants, ectopic expression of miR2111 significantly enhanced lateral root emergence with a decrease in lateral root length and average root diameter. In contrast, hairy roots constitutively expressing the target mimic construct exhibited reduced lateral root density. Overall, these findings demonstrate that miR2111 is both the critical shoot-to-root factor that positively regulates root nodule development, and also acts to shape root system architecture via orchestrating the degree of root branching, as well as the length and thickness of lateral roots.

scholarly journals Lateral Root Traits of Taxodium Hybrid ‘Zhongshanshan 406’ in Response to Drought Stress

HortScience ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 547-551
Author(s):  
Qin Shi ◽  
Yunlong Yin ◽  
Zhiquan Wang ◽  
Wencai Fan ◽  
Jinbo Guo ◽  
...  
Keyword(s):  
Drought Stress ◽  
Surface Area ◽  
Root Length ◽  
Lateral Root ◽  
Plant Root ◽  
Lateral Roots ◽  
Specific Root Length ◽  
Root Traits ◽  
Root Tip ◽  
Root Surface Area

Roots are vital organs for resource uptake. However, the knowledge regarding the extent by which responses in roots influence plant resistance is still poorly known. In this study, we examined the morphological and physiological responses of lateral roots of Taxodium hybrid ‘Zhongshanshan 406’ (Taxodium mucronatum♀ and Taxodium distichum♂, T. 406) to 8 (DS-8) and 12 days (DS-12) drought. Control plants (CK-8 and CK-12) were well-watered throughout the experiment. Results indicated that drought resulted in significantly decreased root length, surface area, volume, and biomass and a relatively high death rate of roots (>2 mm). Specific root length (SRL) and specific root surface area (SRA) of drought-stressed T. 406 plants were reduced to enhance resource uptake. Meanwhile, root relative water content (RWC) of T. 406 plants in CK-12 treatment was 5.81 times of those in DS-12 treatment. Under drought stress and root superoxide dismutase and ascorbic acid (ASA) activities, proline and hydrogen peroxide (H2O2) contents consistently increased to benefit the elimination of O2−. At the ultrastructural level, the organelle structure of T. 406 plant root tip was visibly damaged because of dehydration. The nucleus swelled and then exhibited uncommon features of disorganization and disruption. In short, our results provided substantial information about lateral root traits of T. 406 plants in response to drought stress, which is crucial to improve the drought resistance of Taxodium hybrid in the future breeding.

Application of Phytohormones to Pea Roots After Removal of the Apex: Effect on Lateral Root Production

1979 ◽  
Vol 6 (2) ◽  
pp. 195 ◽  
Author(s):  
PB Goodwin ◽  
SC Morris
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Production ◽  
Root Tip ◽  
Naphthaleneacetic Acid ◽  
Root Initiation ◽  
Lateral Root Initiation ◽  
Lateral Bud ◽  
Bud Growth

Removal of 2 mm of the primary root tip of Pisum sativum caused a complete halt to primary root elongation, but did not alter the total number of laterals formed. The auxins indole-3-acetic acid and 1-naphthaleneacetic acid, when applied to the stump in a lanolin emulsion, increased the number of lateral roots. High levels of abscisic acid and low levels of the cytokinins N6-benzylaminopurine and N6-(γ, γ-dimethylallylamino)purine, and of the gibberellins GA3 and GA7, resulted in decreased lateral root production. Kinetin was without effect. There appears to be an inverse relationship between auxins and cytokinins in root/shoot growth coordination. Auxins, which are produced in the shoot tip, inhibit lateral bud growth but promote lateral root initiation. Cytokinins, which are produced in the root tip, inhibit lateral root initiation, but promote lateral stem growth.

scholarly journals Variation in Phosphorus Availability, Root Architecture Attributes, and Onset of Storage Root Formation among Sweetpotato Cultivars

HortScience ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 1903-1911
Author(s):  
Arthur Villordon ◽  
Jeffrey C. Gregorie ◽  
Don LaBonte
Keyword(s):  
Lateral Root ◽  
Ipomoea Batatas ◽  
Root Formation ◽  
Primary Root ◽  
Root Traits ◽  
Primary Objective ◽  
Specific Information ◽  
Storage Root ◽  
Planting Dates ◽  
Species Specific

The primary objective of this work was to generate species-specific information about root architectural responses to variations in inorganic phosphate (Pi) availability at the onset of storage root formation among six sweetpotato (Ipomoea batatas) cultivars. Three Pi levels were used: 0 (low Pi); 0.17 (medium Pi); and 0.34 (high Pi) g/pot triple super phosphate (0N–46P–0K). The check cultivar ‘Bayou Belle’ (BB) consistently showed evidence of storage root formation at 15 days in adventitious roots (ARs) grown across three Pi levels and two planting dates (PDs). Storage root formation was also detected in ‘Orleans’ (OR) and ‘Beauregard’ (BX), but it was less consistent relative to BB. In general, BB had the lowest adventitious root (AR) number relative to the other cultivars, but the magnitudes of difference varied with Pi availability and PD. With the first PD, BX had a 45% higher AR number compared with BB in low Pi conditions; however, there were no differences in the second PD. Within cultivars, BX and Okinawa grown in low Pi showed combined 17% and 24% reductions in primary root length (PRL) relative to roots grown in high Pi. BB had a higher lateral root number (LRN) and lateral root density (LRD) across Pi levels, corroborating prior data regarding the association of these root architectural attributes with the onset of storage root formation. The experimental data support the hypothesis regarding the existence of genetic variation for Pi efficiency in sweetpotato and that some well-documented Pi-efficient root traits like high LRN and LRD are indirectly selected for in-breeding programs that focus on early storage root formation and stable yields across environments.

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